Steam Generator and Laundry Machine Comprising the Same

ABSTRACT

The present invention relates to laundry machines, and more particularly, to a steam generator for a laundry machine and a laundry machine with the same. The present invention provides a steam generator including a case having a space for turning water into steam, a heater for heating the water for generating the steam, and at least two overheating preventive means for preventing overheating of the heater, and a laundry machine with the same.

TECHNICAL FIELD

The present invention relates to laundry machines, and moreparticularly, to a steam generator for a laundry machine and a laundrymachine with the same.

BACKGROUND ART

In general, of washing machines, a drum type washing machine, washinglaundry by using friction between a drum rotated by a motor and thelaundry in a state detergent and washing water, and the laundry isintroduced to the drum, has almost no damage, or entangling of thelaundry, and can provide a washing effect of rubbing and pounding thelaundry.

FIG. 1 illustrates a longitudinal section of a related art drum typewashing machine.

Referring to FIG. 1, the related art drum type washing machine isprovided with a body 10 of an exterior thereof, a tub 20 in the body 10,a drum 30 rotatably mounted in the tub 20 having lifters 35 on an insidecircumferential surface, and driving means 70 for driving the drum 30.

On a front of the body 10, There is a door 40 provided to apredetermined position so as to be matched with an opening in the drum30, with a gasket 50 between the door 40 and the drum 30 for maintainingsealing of the drum 30.

The tub 20 has dampers at opposite lower sides of an outsidecircumference secured to the body 10.

The driving means 70 is provided with a driving motor 71 for driving thedrum 30, and a belt 72 connected to a belt pulley 73 for transmission ofa driving power from the driving motor 71 to the drum 30.

If a user gives an order to perform general washing, a controller (notshown) of the drum type washing machine which controls operation of thewashing machine progresses washing, rinsing, final spinning insuccession, to washing the laundry.

In the washing, separation of dirt is made by means of the detergent,and by means of impact, friction, and bending and stretching caused bycontinuous lifting and dropping of the laundry by the lifters 35 as thedrum 30 is rotated continuously.

In the rinsing, the step of rinsing is performed, in which residualdetergent and dirt produced as the washing is progressed by supplyingnew washing water and repetitive rotation of the drum 30 is separatedfrom the laundry.

In the final spinning, the drum 30 is rotated at a high speed (approx.800 RPM˜1300 RPM) to remove moisture from the laundry.

Moreover, recently, for reducing power consumption and washing waterused for the washing, a drum type washing machine having a steamgenerator 80 mounted thereto is provided.

Referring to FIG. 2, a related art steam generator 80 is provided with acase 82 of an exterior thereof to form a space for holding water, and aheater 84 for heating the water.

The case 82 has one side with a water inlet (not shown) connected to awater supply pipe (not shown) for introduction of water to an inside ofthe case 82, and the other side with an outlet (not shown) connected toa steam supply pipe (not shown) or the like for supplying steamgenerated by heating the water introduced thereto with the heater 84 tothe drum 30 of the washing machine.

It is preferable that the heater 84 is mounted on a lower side of thecase 82 for heating the water directly in a state the heater 84 issubmerged in the water held in the case 82 completely.

In this instance, a sheath heater is suitable for the heater, which hasa high heat efficiency and can heat the water within a short timeperiod.

In the meantime, there is a temperature sensor 88 at a center of thecase 82 for measuring a temperature of the water in the case 82.

Moreover, there is overheating preventive means 86, such as thermo-fuse,at one end of the heater 84 for preventing the heater 84 from beingoverheated to damage the heater 84 itself and components around theheater 84.

The overheating preventive means 86 is designed to be short circuited ina case the heater 84 is overheated, to cut off power to the heater 84,to prevent the heater 84 from being overheated anymore.

The operation of the related art steam generator of a washing machinewill be described.

Upon starting the washing, the water is supplied to the case 82 throughthe water inlet.

The water introduced to the case 82 is heated with the heater 84, and isturned into steam, and the steam is introduced to the drum 30 holdingthe laundry through the outlet (not shown) in the case 82, to improvewashing efficiency by wetting and soaking of the laundry.

After finishing the wetting and soaking of the laundry, the steamgenerator 80 is stopped, and a series of washing steps are performed, tofinish the washing

However, the related art steam generator of the washing machine has thefollowing drawbacks.

First, referring to FIG. 3, the steam generator 80 can be tilted due tonegligence of the worker or failure of installation of the washingmachine in a horizontal position.

If a water level of the steam generator 80 becomes low under abovestate, to expose one end of the heater 84 over the water surface, theexpose portion is overheated as the heater 84 is kept operated.

In this instance, since the overheating preventive means 86 at one sideend of the heater 84 is in a submerged state, the overheating preventivemeans 86 fails to sense overheating of the exposed end of the heater 84,and the temperature sensor 88, at the center of the case 82 submerged inthe water, also fails to sense the overheating of an inside of the case.

Consequently, as the heater 84 fails to stop, but is kept overheating,the case 82 is likely to deform by the heat from the heater 84, or if itis excessive, the case 82 deformed by the heat is come into contact withthe heater 84 to cause an outbreak of fire.

DISCLOSURE OF INVENTION Technical Problem

An object of the present invention is to provide a steam generator for alaundry machine, in which the heater is not overheated, to cause thermaldeformation or outbreak of fire even if the steam generator is tilted;and a laundry machine having the same.

Technical Solution

The object of the present invention can be achieved by providing a steamgenerator for a laundry machine including a case having a space forturning water into steam, a heater for heating the water for generatingthe steam, and at least two overheating preventive means for preventingoverheating of the heater.

It is preferable that the overheating means is means for cutting offpower to the heater, actually.

In more detail, the overheating preventive means includes at least oneof a thermo-fuse, thermister, and thermostat. That is, the overheatingpreventive means can prevent overheating of the heater by means ofpermanent or selective electric short circuit or substantial electricshort circuit owing to a very high resistance.

Preferably, the overheating preventive means includes first overheatingpreventive means at one side of the heater, and second overheating meansat the other side of the heater. That is, if there are a plurality ofoverheating preventive means, it is preferable that the overheatingpreventive means are provided at opposite sides.

Preferably, the first overheating preventive means and the secondoverheating preventive means are of types different from each other.

In the meantime, in another aspect of the present invention, a steamgenerator for a laundry machine includes a case having a water inlet forintroduction of water thereto, an outlet for discharging steam, and areceiver for holding water introduced thereto, a heater for heating thewater in the case for generating the steam, and at least two overheatingpreventive means for preventing overheating of the heater.

Preferably, the heater is mounted in the receiver of the case, and asheath heater. Preferably, the heater is mounted such that the heater ispassed through one side wall of the case and extended toward a directionof a side wall opposite the one side wall.

Preferably, the overheating preventive means includes first overheatingpreventive means in the vicinity of one side wall of the case, andsecond overheating means in the vicinity of a side wall opposite to theone side wall.

Preferably, the first overheating preventive means senses overheating ofthe heater by means of thermal conduction substantially, and morespecifically, may be a thermo-fuse, or thermostat.

On the other hand, preferably the second overheating preventive meanssenses overheating of the heater by means of radiation of convection ofheat substantially, and more specifically, may be a thermister having aresistance varied with a temperature. Preferably, the resistance of thethermister rises sharply if a temperature of the heater is higher than areference temperature, to cat off power to the heater, substantially. Ofcourse, the types of the first overheating means and the secondoverheating means may be interchanged.

In another aspect of the present invention, a laundry machine includes abody of an exterior of the laundry machine, a tub in the body, a drumrotatably mounted in the tub, and a steam generator for supplying steamto the tub or the drum, wherein the steam generator includes a casehaving a water inlet for introduction of water thereto, an outlet fordischarging steam, and a receiver for holding water introduced thereto,a heater for heating the water in the case for generating the steam, anda plurality of overheating preventive means of types different from oneanother for preventing overheating of the heater.

The plurality of overheating preventive means may include firstoverheating preventive means on one side of the heater in the case, andsecond overheating means on the other side of the heater.

ADVANTAGEOUS EFFECTS

The steam generator for a washing machine of the present invention hasthe following advantages.

First, since the second overheating preventive means senses overheatingof the heater, and stops the heater even if the heater is overheated dueto exposure of the other end of the heater coming from tilting of thesteam generator, thermal deformation of the case and outbreak of firecan be prevented, to improve safety of the product.

The prevention of overheating of the end of the heater improves alifetime and safety of the heater.

Third, the provision of different types of overheating preventive meanspermits to prevent the overheating of the heater with high reliability,to prevent damage coming from overheating of the heater.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiment(s) of theinvention and together with the description serve to explain theprinciple of the invention. In the drawings;

FIG. 1 illustrates a longitudinal section of a related art drum typewashing machine;

FIG. 2 illustrates a perspective view of a related art steam generator,with a partial cut away view;

FIG. 3 illustrates a diagram of the steam generator in FIG. 2 when thesteam generator is tilted;

FIG. 4 illustrates a perspective view of a steam generator for a washingmachine in accordance with a preferred embodiment of the presentinvention;

FIG. 5 illustrates a bottom view of the steam generator in FIG. 4 seenfrom an inside thereof; and

FIG. 6 illustrates a diagram of the steam generator in FIG. 4 when thesteam generator is tilted.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

FIG. 4 illustrates a perspective view of a steam generator for a washingmachine in accordance with a preferred embodiment of the presentinvention, FIG. 5 illustrates a bottom view of the steam generator inFIG. 4 seen from an inside thereof, and FIG. 6 illustrates a diagram ofthe steam generator in FIG. 4 when the steam generator is tilted.

Referring to FIGS. 4 and 5, the steam generator 180 includes a casehaving a space for turning water into steam, a heater for heating thewater for generating the steam, and at least two overheating preventivemeans for preventing overheating of the heater.

The case 182 has a water inlet 181 at one side, and an outlet 183 at theother side for discharging steam generated as the water introducedthrough the water inlet 181 is heated toward a drum 30 (see FIG. 1). Thecase 182 has a predetermined volume for holding a predetermined amountof water.

There is a heater 184 for heating the water in the case 182. It ispreferable that the heater 184 mounted to a lower side of the case 182for heating the water even if a water level in the case 182 is low.

Moreover, it is preferable that the heater is a sheath heaters which hashigh thermal efficiency and can heat the water within a comparativelyshort time period.

Referring to FIGS. 4 and 5, it is preferable that the heater 184 ismounted such that the heater 184 is passed thrash one side wall of thecase 182, and extended to an opposite side wall of the one side wall,for easy detachment of the heater.

The heater 184 includes first overheating preventive means 186 forpreventing overheating of the heater 184.

It is preferable that the first overheating preventive means 186 is athermo-fuse at one end of the heater 184 for short circuiting atoverheating of the heater 184 to cut off power to the heater 184, forpreventing overheating of the heater 184. That is, in a case theoverheating of the heater is prevented by using such a thermo-fuse, itis required to replace the thermo-fuse with new one because thethermo-fuse is short circuited, permanently.

FIG. 4 illustrates a thermo-fuse 186 mounted between both ends of theheater for easy replacement of the thermo-fuse 186, and FIG. 5illustrates a thermo-fuse 186 at both ends of the heater.

In a case of the thermo-fuse illustrated in FIG. 4, though heat of theheater is transmitted to the thermo-fuse, not directly, but indirectlythrash other media, but, in a case of the thermo-fuse illustrated inFIG. 5, the heat of the heater is transmitted to the thermo-fusedirectly. According to this, the first overheating preventive means hasthe heat of the heater transmitted thereto by thermal conduction,substantially.

Moreover, besides the first overheating preventive means 186, there issecond overheating preventive means 188 for measuring a temperature ofthe water in the case 182 or an inside of the case 182.

In more detail, it is preferable that the second overheating preventivemeans 188 is placed in the case 182 through a top surface thereof at aposition opposite to the first overheating preventive means 186 at oneend of the heater 184, i.e., at the other end of the heater 184.

This is for measuring radiant heat emitted from the other end of theheater 184 as the second overheating means 188 is mounted over the otherend of the heater 184. Of course, the heat from the heater can betransmitted to the second overheating preventive means through the steamin the steam generator or convection of the air. Therefore, the secondoverheating preventive means senses overheating by means of radiation,or convection, substantially.

It is preferable that the power to the heater 184 is cut off forpreventing the heater 184 from emitting no more heat, if the heat sensedat the second overheating preventive means 188 is higher than areference temperature.

In this instance, though it is preferable that the reference temperatureis a temperature a material of the case 182 can resist, since thetemperature is varied with the material, and a detailed structure of theinside of the case 182, detailed description of which will be omitted.

Accordingly, the second overheating preventive means 188 serves toprevent overheating and deformation of the case 182 by measuring radiantheat emitted from the other end of the heater 184, and cutting off thepower to the heater 184 if the radiant heat is higher than the referencetemperature.

The second overheating means 188 may be a thermister having a resistancevaried with the heat measured. In this case, it is preferable that theresistance of the thermister rises sharply at a temperature higher thanthe reference temperature where it is determined that the heater isoverheated. That is, a very high resistance cuts off the power to theheater, actually. In other words, though the thermister does not shortcircuit physically, it can be assumed that a short circuit is made,substantially.

In the meantime, besides the thermister, as the second overheating means188, a thermostat may be used, of which volume expands, and contractsaccording to heat. That is, the thermostat is designed to cut off acurrent to the heater 184 as the thermostat expands thermally if theother end of the heater 184 is overheated. As one example of thethermostat, a bimetal may be used.

Since a structure of the thermostat for cutting off the current to theheater 184 is known, a detailed description of which will be omitted.

If is preferable that the second overheating preventive means and thesecond overheating preventive means is overheating preventive meanshaving types different from each other for preventing overheating of theheater with higher reliability, inclusive of heat sensing structures andmajor heat transfer types.

For an example, if the first overheating preventive means is of athermostat type that senses heat in a mode of radiation, the secondoverheating preventive means may be a thermo-fuse for sensing the heatin a mode of heat transfer.

In the meantime, though not shown, there may be a water level sensor(not shown) for measuring a water level of the in the case 182.

Therefore, in the steam generator for the washing machine of the presentinvention, the water is introduced to the case 182 through the waterinlet 181, the heater 184 heats water introduced to the case 182 togenerate steam, and the steam generated thus is supplied to the drum 30(see FIG. 1) through the outlet 183.

By detecting a remained amount of water in the case 182 by the waterlevel sensor (not shown), overheating of the heater 184 is prevented,caused by operation of the heater 184 despite of shortage of water inthe case 182.

Moreover, in a case the heater 184 is overheated by unexpected fault ormalfunction, the first overheating means 186 cuts of the current to theheater 184, to prevent any more overheating of the heater 184.

In this instance, referring to FIG. 6, because the washing machine istilted due to reasons, such as installation of the washing machine on afloor which is not horizontal, or the steam generator 180 is assembledin a non-horizontal state due to mistake of a worker, the firstoverheating means 186 may not function, properly.

In more detail, in a case the steam generator 180 is tilted such that aportion of the first overheating preventive means 186 of the heater 184is submerged in the water, and an opposite end of the portion the firstoverheating preventive means 186 is mounted is exposed from a watersurface, since a neighborhood of the heater 184 having the firstoverheating preventive means 186 mounted thereon is submerged in thewater, the heater 184 is kept operating.

However, because the opposite end of the portion having the firstoverheating preventive means 186 mounted thereon of the heater 184 isexposed from the water surface, to fail to be cooled down by the water,but overheated, the opposite end emits radiant heat to an environment.

In this instance, since the second overheating preventive means 188 ispositioned over the opposite end of the portion where the firstoverheating preventive means 186 of the heater 184 is mounted, thesecond overheating preventive means 188 measures radiant heat emittedfrom the heater 184 exposed from the water surface, to stop operation ofthe heater 184 if the heater 184 is overheated over the referencetemperature.

Of course, in a case the steam generator is tilted opposite to theposition illustrated in FIG. 6, since the first overheating preventivemeans is exposed from the water surface even if the second overheatingpreventive means is submerged in the water, the overheating of theheater can be prevented by the first overheating preventive means.

Therefore, according to the steam generator for a washing machine of thepresent invention, deformation or outbreak of fire caused by overheatingof the heater 184 can be prevented.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

INDUSTRIAL APPLICABILITY

Included to the detailed description of the present invention.

1. A steam generator for a laundry machine comprising: a case having aspace to turn water into steam; a heater to heat the water and togenerate the steam; and at least a first and second overheatingpreventers to prevent overheating of the heater, wherein the firstoverheating preventer is located at one side of the heater and thesecond overheating preventer is located at the other side of the heater.2. The steam generator as claimed in claim 1, wherein at least one ofthe first and second overheating preventers includes a thermo-fuse. 3.The steam generator as claimed in claim 2, wherein the thermo-fuse isprovided to cut off a current to the heater when the heater isoverheated.
 4. The steam generator as claimed in claim 1, wherein atleast one of the first and second overheating preventer includes athermister.
 5. The steam generator as claimed in claim 1, wherein atleast one of the first and second overheating preventer includes athermostat.
 6. (canceled)
 7. The steam generator as claimed in claim 1,wherein the first overheating preventer and the second overheatingpreventer are of different types.
 8. A steam generator for a laundrymachine comprising: a case having a water inlet to receive water and anoutlet to discharge steam; a heater to heat the water in the case togenerate the steam; and at least a first and second overheatingpreventers to prevent overheating of the heater, wherein the firstoverheating preventer is located at one side of the heater and thesecond overheating preventer is located at the other side of the heater.9. The steam generator as claimed in claim 8, wherein the heater ismounted in the case.
 10. The steam generator as claimed in claim 9,wherein the heater is a sheath heater.
 11. The steam generator asclaimed in claim 10, wherein the heater is mounted such that the heaterpasses through one side wall of the case and extends toward a directionof a side wall opposite the one side wall.
 12. The steam generator asclaimed in claim 11, wherein the first overheating preventer is in thevicinity of the one side wall of the case and the second preventer is inthe vicinity of the side wall opposite to the one side wall.
 13. Thesteam generator as claimed in claim 8, wherein the first overheatingpreventer and the second overheating preventer are of different types.14. The steam generator as claimed in claim 13, wherein the firstoverheating preventer senses overheating of the heater through ofthermal conduction.
 15. The steam generator as claimed in claim 14,wherein the first overheating preventer is a thermo-fuse or athermostat.
 16. The steam generator as claimed in claim 13, wherein thesecond overheating preventer senses overheating of the heater throughheat convection.
 17. The steam generator as claimed in claim 16, whereinthe second overheating preventer is a thermister having a resistancethat varies with temperature.
 18. The steam generator as claimed inclaim 17, wherein the resistance of the thermister rises sharply if atemperature of the heater is higher than a reference temperature, tosubstantially cut off power to the heater.
 19. A laundry machinecomprising: a body; a drum rotatably mounted in the body; and a steamgenerator to generate steam to be supplied into the drum, wherein thesteam generator includes; a case having a water inlet to receive waterand an outlet to discharge the steam, a heater to heat the water and togenerate the steam, first overheating preventer located at one side ofthe heater, and second overheating preventer located at the other sideof the heater.
 20. The laundry machine as claimed in claim 19, whereinthe first overheating preventer and the second overheating preventer areof different types.